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git.proxmox.com Git - mirror_ubuntu-jammy-kernel.git/blob - arch/x86/kernel/crash_dump_64.c
2 * Memory preserving reboot related code.
4 * Created by: Hariprasad Nellitheertha (hari@in.ibm.com)
5 * Copyright (C) IBM Corporation, 2004. All rights reserved
8 #include <linux/errno.h>
9 #include <linux/crash_dump.h>
11 #include <asm/uaccess.h>
15 * copy_oldmem_page - copy one page from "oldmem"
16 * @pfn: page frame number to be copied
17 * @buf: target memory address for the copy; this can be in kernel address
18 * space or user address space (see @userbuf)
19 * @csize: number of bytes to copy
20 * @offset: offset in bytes into the page (based on pfn) to begin the copy
21 * @userbuf: if set, @buf is in user address space, use copy_to_user(),
22 * otherwise @buf is in kernel address space, use memcpy().
24 * Copy a page from "oldmem". For this page, there is no pte mapped
25 * in the current kernel. We stitch up a pte, similar to kmap_atomic.
27 ssize_t
copy_oldmem_page(unsigned long pfn
, char *buf
,
28 size_t csize
, unsigned long offset
, int userbuf
)
35 vaddr
= ioremap(pfn
<< PAGE_SHIFT
, PAGE_SIZE
);
38 if (copy_to_user(buf
, (vaddr
+ offset
), csize
)) {
43 memcpy(buf
, (vaddr
+ offset
), csize
);